Controlled shear point fiber optic cable adapter

Abstract

A fiber optic adapter is provided which controls the shear point for a fiber optic wiring system in a traffic control box and other fiber optic applications. The fiber optic adapter includes a bottom disc with a shear chamber and cutting blade, a center gasket, and a top disc with a splice chamber and splice block, for field assembly. Once the fiber optic cables have been positioned in the fiber optic adapter, the adapter is securely mounted to an immobile object in the control box. When a triggering event occurs, such as an accident at the traffic control box, the fiber optic cable is caused to engage the cutting blade to shear the fiber optic cable inside the adapter and not elsewhere in the fiber optic wiring system.

The invention claimed is: 
     
       1. A fiber optic adapter for controlling the shear point of conductors in a fiber optic wiring system, said fiber optic adapter being located in proximity to a conduit opening through which incoming fiber optic conductors are extended, said fiber optic adapter comprising:
 a bottom disc, said bottom disc including a raised edge formed around the inner circumference of the bottom disc to form a shear chamber, a rotatable spool secured in the center of the bottom disc, a cutting blade secured in a blade fixture in proximity to the raised edge, and an access aperture formed in the raised edge to facilitate the positioning of fiber optic conductors adjacent to the cutting blade in the shear chamber of the bottom disc; 
 a top disc, said top disc including a raised edge formed around the inner circumference of the top disc to form a splice chamber, a splice holder, and an access aperture formed in the raised edge to facilitate the positioning of fiber optic conductors in the splice chamber of the top disc; 
 a center gasket positioned between the top disc and the bottom disc, whereby the center gasket closes the shear chamber of the bottom disc and closes the splice chamber of the top disc, said center gasket including a slotted aperture to facilitate the extension of fiber optic conductors between the shear chamber and the splice chamber; and 
 a plurality of assembly screws for securing the bottom disc, the center gasket, and the top disc into the assembled fiber optic adapter of the present invention, whereby a triggering event will create tension on the fiber optic conductors in the fiber optic adapter, such that the fiber optic conductors are sheared inside the shear chamber of the fiber optic adapter when the fiber optic conductors engage the cutting blade. 
 
     
     
       2. The fiber optic adapter of  claim 1 , wherein said bottom disc includes a retention clip secured to the bottom disc in proximity to the cutting blade. 
     
     
       3. The fiber optic adapter of  claim 1 , including a plurality of mounting holes extending from the outer edge of the top plate, through the center gasket, and through the bottom disc. 
     
     
       4. The fiber optic adapter of  claim 1 , wherein the access aperture of the bottom disc includes a gasket and the access aperture of the top disc includes a gasket, whereby said access apertures are sealed to prevent moisture from entering the shear chamber and the splice chamber. 
     
     
       5. The fiber optic adapter of  claim 1 , wherein the center gasket is made from rubber or from polymer, whereby said center gasket forms a seal between the bottom disc and the top disc to prevent moisture from entering the shear chamber and the splice chamber of the fiber optic adapter. 
     
     
       6. The fiber optic adapter of  claim 1 , wherein said blade fixture includes a slot for securing the cutting blade, whereby the cutting blade can be removed and reinserted in the slot when positioning fiber optic conductors in the shear chamber during the assembly process, and wherein the cutting blade is secured in the slot when the center gasket is assembled between the bottom disc and the top disc. 
     
     
       7. The fiber optic adapter of  claim 1 , including a plurality of splice holders mounted in the splice chamber of the top disc. 
     
     
       8. A method for connecting, in a control box, a fiber optic wire having a plurality of conductors to a corresponding fiber optic wire drop segment having a plurality of conductors, and using a fiber optic adapter to provide shear point control, such that when the control box is damaged and stress is applied to the fiber optic wire and the wire segment, the shear point for the stressed fiber optic wire and fiber optic drop wire segment occurs at the fiber optic adapter, the method comprising:
 stripping an outer jacket of an end segment of the fiber optic wire to expose the conductors; 
 positioning conductors of the fiber optic wire through an access aperture into a bottom disc of the fiber optic adapter and securing the conductors adjacent to a cutting blade in a shear chamber of the bottom disc; 
 positioning the conductors of the fiber optic wire through an aperture of a center gasket and into a splice chamber of a top disc; 
 positioning ends of the conductors of the fiber optic wire in a splice holder located in the splice chamber; 
 positioning conductors of the fiber optic drop wire segment through an access aperture formed in the top disc of the fiber optic adapter and positioning ends of the conductors in the splice holder in the splice chamber of the top disc; 
 splicing the ends of the conductors of the fiber optic wire to the ends of the conductors of the fiber optic drop wire segment and positioning the conductors in the splice holder; 
 securing the bottom disc, the center gasket, and the top disc, using the assembly screws, to assemble the fiber optic adapter, and 
 mounting the fiber optic adapter to a secure surface in the control box. 
 
     
     
       9. The method of  claim 8 , including the positioning of a gasket into the access aperture of the bottom disc and the positioning of a gasket into the access aperture of the top disc, whereby the assembled fiber optic adapter is sealed against moisture. 
     
     
       10. The method of  claim 8 , wherein positioning of the conductors of the fiber optic wire in the bottom disc includes spooling the conductors about a rotatable center spool positioned in the shear chamber of the bottom disc. 
     
     
       11. The method of  claim 8 , wherein positioning of the conductors of the fiber optic wire in the top disc includes spooling the conductors about the splice holder positioned in the splice chamber of the top disc. 
     
     
       12. The method of  claim 8 , including the additional step of separating a strength member from the conductors before positioning the conductors adjacent to the cutting blade in the shear chamber of the bottom disc. 
     
     
       13. A method for connecting, in a control box, a fiber optic wire having a plurality of conductors to a plurality of control system components, and using a fiber optic adapter to provide shear point control, such that when the control box is damaged and stress is applied to the fiber optic wire, the shear point for the stressed fiber optic wire occurs at the fiber optic adapter, the method comprising:
 stripping an outer jacket of a non-end segment of the fiber optic wire to expose the conductors; 
 positioning conductors of the fiber optic wire through an access aperture into a bottom disc of the fiber optic adapter and securing the conductors adjacent to a cutting blade in a shear chamber of the bottom disc; 
 positioning the conductors of the fiber optic wire through an aperture of a center gasket and into a splice chamber of a top disc; 
 positioning the conductors of the fiber optic wire in the splice chamber of the top disc; 
 positioning conductors of the fiber optic wire to an access aperture formed in the top disc of the fiber optic adapter; 
 extending the fiber optic wire to the control system components and connecting ends of the conductors of the fiber optic wire to terminals for the control system components; 
 securing the bottom disc, the center gasket, and the top disc, using the assembly screws, to assemble the fiber optic adapter, and 
 mounting the fiber optic adapter to a secure surface in the control box. 
 
     
     
       14. The method of  claim 13 , including the positioning of a gasket into the access aperture of the bottom disc and the positioning of a gasket into the access aperture of the top disc, whereby the assembled fiber optic adapter is sealed against moisture. 
     
     
       15. The method of  claim 13 , wherein positioning of the conductors of the fiber optic wire in the bottom disc includes spooling the conductors about a rotatable center spool positioned in the shear chamber of the bottom disc. 
     
     
       16. The method of  claim 13 , wherein positioning of the conductors of the fiber optic wire in the top disc includes spooling the conductors about the splice holder positioned in the splice chamber of the top disc. 
     
     
       17. The method of  claim 13 , including the additional step of separating a strength member from the conductors before positioning the conductors adjacent to the cutting blade in the shear chamber of the bottom disc.